Dermatochalasis causing apparent bitemporal hemianopsia.

We describe a previously unreported cause of apparent bitemporal hemianopsia. Three patients with bilateral dermatochalasis underwent Humphrey visual field (HVF) testing in anticipation of corrective blepharoplasty. Unexpectedly, the HVF showed bitemporal hemianopsia in each case, prompting magnetic resonance imaging of the brain in one case. The scan was negative. The HVF tests were repeated with the upper eyelids taped in elevation, and were normal. We conclude that the bitemporal hemianopic defects in our patients resulted from the testing strategy employed by the HVF analyzer software to measure the visual field. Reasons for these artifactual results are discussed. Clinicians should be aware of this uncommon cause of bitemporal hemianopic visual field defects.